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Imagine a whole world without stopping. Before you is a volcanic landscape, without flora and fauna. Shallow bodies of water are scattered throughout this gray and black expanse. In each of these natural pools there is a precise combination of chemicals and physical conditions that could act as the source of life on our planet.
Some scientists have theorized that the scene may have looked very similar, rather than an ocean setting, when life first appeared on Earth about 4 billion years ago, and a study focused on on today’s lake in the Canadian province of British Columbia with a new offering. support for that idea.
The shallow, salty body of water resting on volcanic rock — called Last Chance Lake — holds clues that carbonate-rich lakes in the Old World may have been a “cradle of life,” according to study co-author David Catling, a professor at University Washington. the geosciences. The result, published in the journal Nature on January 9, could advance scientific understanding of how life began.
“We were able to look for the specific conditions that humans use to synthesize the building blocks of life in nature,” Catling said. “We think we have a very promising place for the origin of life.”
Catling and his colleagues first became aware of the lake as a place to focus their research after a literature review of an unpublished master’s thesis from the 1990s found unusual phosphate levels recorded there. But the researchers had to see it for themselves.
Last Chance Lake
Last Chance Lake is no more than 1 foot deep. Located on a volcanic plateau in British Columbia over 1,000 meters (3,280 feet) above sea level, it contains the highest levels of concentrated phosphate ever recorded in any natural body of water in the world.
A vital component of biological molecules, phosphate is a chemical compound containing the life-sustaining element phosphorus. It is found in molecules such as RNA and DNA as well as ATP, a molecule necessary for the production of energy in all life forms. The abundance of phosphate at Last Chance Lake is more than 1,000 times greater than what is typical of oceans or lakes, according to Sebastian Haas, a postdoctoral researcher studying the microbiology and chemistry of aquatic environments at the University of Washington who led the paper .
Between 2021 and 2022, the team of researchers visited Last Chance Lake to collect and analyze water and sediment samples.
That’s when they discovered that Last Chance Lake is not only a hot bed for phosphate but also for the mineral dolomite, which allows phosphorus to build up in this environment and was formed in response to a reaction in the lake between calcium, magnesium and carbonate. Due to the compounding chemical processes, influenced by minerals from the volcanic rock on which the lake was formed, as well as the dry climate, the unique phosphate concentrations were effectively produced – a set of conditions that researchers believe could have led to the emergence of the lead them to life once. Earth, according to Haas.
“We are adding credibility to the idea that this type of environment would be favorable for the origin of life, and that it is plausible,” he said.
Last Chance Lake is not 4 billion years old – in fact, it is estimated to have been around less than 10,000 years. The site is just a modern analogue, or a natural picture of the past that finally gives scientists a chance to better understand what the early Earth would have looked like outside of a laboratory.
“There is every reason to believe that similar lakes would have first occurred on earth about 4 billion years ago, because the volcanic rocks that make up Last Chance Lake are a prerequisite for the formation of soda lakes,” said Haas. “And what we’re showing in part here is that soda lake water chemistry is a prerequisite for these high phosphate levels.”
Darwin’s small hot ponds
“Soda lakes” such as Last Chance Lake are shallow bodies of water with dissolved sodium and carbonate – similar to baking soda – that typically result from interactions between water and volcanic rocks. They can be found all over the world but are much less common than other saline water bodies.
“These lakes, they have the highest phosphate levels that match what people use in the lab to make (genetic molecules),” Catling said.
When scientists have tried to replicate in the laboratory the chemical reactions carried out by the biomolecules believed to be crucial to the origin of life, the necessary phosphate concentrations are up to a million times higher than normally found in the world’s natural bodies of water.
“If you had these types of lakes on the ancient Earth, they would be high in phosphate, just like Last Chance Lake,” Catling added.
Bodies of water like this have long been on the radar of scientists as potential sources of primordial life. In the 1800s, Charles Darwin first wrote about his “warm little pond” theory, which suggested that warm, shallow, phosphate-rich lakes could have been the first life molecules to form.
“Part of (Darwin’s) imagination was these bubbling pools … like Yellowstone,” said Matthew Pasek, a professor at the University of South Florida who studies phosphorus chemistry and the origins of life sciences.
But this is not the only popular theory of how life first appeared on Earth billions of years ago. Another is that life began in hydrothermal vents in the deep sea.
The new study adds to the body of evidence supporting the small warm pond hypothesis, according to Pasek, who was not involved in the research.
“The main point, that you can have such high phosphate concentrations in these pools, is certainly reinforced by this finding,” he said. “And it shows, ‘This is how that can happen.'”
Still, phosphate in mass abundance is not the only substance required for the initiation of life. That list of prerequisites also includes sources of carbon and nitrogen, as well as the right chemical and physical elements — including phenomena known as wet-dry cycles — that allow necessary compounds and chemical reactions to form.
But the authors said that they are not making the case that today’s Last Chance Lake has all the necessary components for the building blocks of life – just that it is some vital pieces.
“Today’s Last Lake lacks some chemicals that we now think are critical to the origin of life,” Haas said, citing cyanide as one example. Past studies suggest that the substance may have been included in a primordial version of lake soda.
Although this work does not single-handedly solve the question of where life came from,” says Woodward Fischer, a geobiologist at the California Institute of Technology who was not involved in the study, “it points to environments on Earth’s surface today that can scientists. study in more detail to better understand the mechanics responsible for establishing life on our planet and possibly elsewhere.”
The origin of life on earth – and beyond
If life evolved in soda lakes on land, instead of at the bottom of the ocean, that knowledge could theoretically help in the search for evidence of life beyond Earth.
“If you thought life originated at the bottom of the ocean, you might see subglacial oceans on the moons of Saturn and Jupiter,” Haas said. “But if you think that life originated on Earth’s land surfaces, planets like Mars might be much more important.”
The same type of rock formation that produces soda lakes is found on many of the surfaces of rocky planets such as Mars – suggesting that life may have formed in a similar way elsewhere around the globe.
“Understanding how life came to be on Earth is this important to our search for life beyond Earth,” Haas told CNN. “A better understanding of how life originated on Earth informs where to look for life on other planets, or the moons of other planets, in the solar system.”
Ayurella Corn-Muller He has reported for Axios and Climate Central. His book, “Devoured: The Extraordinary Story of Kudzu, the Vine that Ate the South,” is due out in the spring.
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